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package Net::DNS::Resolver::Cygwin;
#
# $Id: Cygwin.pm 291 2005-05-21 07:40:58Z olaf $
#
use strict;
use vars qw(@ISA $VERSION);
use Net::DNS::Resolver::Base ();
@ISA = qw(Net::DNS::Resolver::Base);
$VERSION = (qw$LastChangedRevision: 291 $)[1];
sub getregkey {
my $key = $_[0] . $_[1];
my $value = '';
local *LM;
if (open(LM, "<$key")) {
$value = <LM>;
$value =~ s/\0+$//;
close(LM);
}
return $value;
}
sub init {
my ($class) = @_;
my $defaults = $class->defaults;
local *LM;
my $root = '/proc/registry/HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Tcpip/Parameters/';
unless (-d $root) {
# Doesn't exist, maybe we are on 95/98/Me?
$root = '/proc/registry/HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/VxD/MSTCP/';
-d $root || Carp::croak "can't read registry: $!";
}
# Best effort to find a useful domain name for the current host
# if domain ends up blank, we're probably (?) not connected anywhere
# a DNS server is interesting either...
my $domain = getregkey($root, 'Domain') || getregkey($root, 'DhcpDomain') || '';
# If nothing else, the searchlist should probably contain our own domain
# also see below for domain name devolution if so configured
# (also remove any duplicates later)
my $searchlist = "$domain ";
$searchlist .= getregkey($root, 'SearchList');
# This is (probably) adequate on NT4
my $nt4nameservers = getregkey($root, 'NameServer') || getregkey($root, 'DhcpNameServer');
my $nameservers = "";
#
# but on W2K/XP the registry layout is more advanced due to dynamically
# appearing connections. So we attempt to handle them, too...
# opt to silently fail if something isn't ok (maybe we're on NT4)
# If this doesn't fail override any NT4 style result we found, as it
# may be there but is not valid.
# drop any duplicates later
my $dnsadapters = $root . "DNSRegisteredAdapters/";
if (opendir(LM, $dnsadapters)) {
my @adapters = grep($_ ne "." && $_ ne "..", readdir(LM));
closedir(LM);
foreach my $adapter (@adapters) {
my $regadapter = $dnsadapters . $adapter . '/';
if (-e $regadapter) {
my $ns = getregkey($regadapter, 'DNSServerAddresses') || '';
while (length($ns) >= 4) {
my $addr = join('.', unpack("C4", substr($ns,0,4,"")));
$nameservers .= " $addr";
}
}
}
}
my $interfaces = $root . "Interfaces/";
if (opendir(LM, $interfaces)) {
my @ifacelist = grep($_ ne "." && $_ ne "..", readdir(LM));
closedir(LM);
foreach my $iface (@ifacelist) {
my $regiface = $interfaces . $iface . '/';
if (opendir(LM, $regiface)) {
closedir(LM);
my $ns;
my $ip;
$ip = getregkey($regiface, "IPAddress");
$ns = getregkey($regiface, "NameServer") ||
getregkey($regiface, "DhcpNameServer") || '' unless !$ip || ($ip =~ /0\.0\.0\.0/);
$nameservers .= " $ns" if $ns;
}
}
}
if (!$nameservers) {
$nameservers = $nt4nameservers;
}
if ($domain) {
$defaults->{'domain'} = $domain;
}
my $usedevolution = getregkey($root, 'UseDomainNameDevolution');
if ($searchlist) {
# fix devolution if configured, and simultaneously make sure no dups (but keep the order)
my @a;
my %h;
foreach my $entry (split(m/[\s,]+/, $searchlist)) {
push(@a, $entry) unless $h{$entry};
$h{$entry} = 1;
if ($usedevolution) {
# as long there's more than two pieces, cut
while ($entry =~ m#\..+\.#) {
$entry =~ s#^[^\.]+\.(.+)$#$1#;
push(@a, $entry) unless $h{$entry};
$h{$entry} = 1;
}
}
}
$defaults->{'searchlist'} = \@a;
}
if ($nameservers) {
# just in case dups were introduced...
my @a;
my %h;
foreach my $ns (split(m/[\s,]+/, $nameservers)) {
push @a, $ns unless (!$ns || $h{$ns});
$h{$ns} = 1;
}
$defaults->{'nameservers'} = [map { m/(.*)/ } @a];
}
$class->read_env;
if (!$defaults->{'domain'} && @{$defaults->{'searchlist'}}) {
$defaults->{'domain'} = $defaults->{'searchlist'}[0];
} elsif (!@{$defaults->{'searchlist'}} && $defaults->{'domain'}) {
$defaults->{'searchlist'} = [ $defaults->{'domain'} ];
}
}
1;
__END__
=head1 NAME
Net::DNS::Resolver::Cygwin - Cygwin Resolver Class
=head1 SYNOPSIS
use Net::DNS::Resolver;
=head1 DESCRIPTION
This class implements the cygwin specific portions of C<Net::DNS::Resolver>.
No user serviceable parts inside, see L<Net::DNS::Resolver|Net::DNS::Resolver>
for all your resolving needs.
=head1 COPYRIGHT
Copyright (c) 1997-2002 Michael Fuhr.
Portions Copyright (c) 2002-2004 Chris Reinhardt.
All rights reserved. This program is free software; you may redistribute
it and/or modify it under the same terms as Perl itself.
=head1 SEE ALSO
L<perl(1)>, L<Net::DNS>, L<Net::DNS::Resolver>
=cut
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